Process of reclaiming rubber



RUBBER.

PROCESS 0F REcLAar/Hw APPLICATION FILED DEC. 13, 1920 WL* Pmend l? m1@ M@ WZL UNITED. STATES PATENT; orifice.

anni. muscnawsirn AND WILLIAM w. woon, or Los ANGELES, csmroairm.

rnoonss or ancmmme RUBBER.

To all whom it 1mg] concern:

. Be it known that we, Emi. MUsoHBwsKE and W iLLiAM W. Woon, both citizens of the United States, residing in Los Angeles, county of Los Angeles, State of California,

have jointly inventednew and useful Im-A a manner as to transform it into rubberv products, onrubbei stock, of a quality equal used equally as well.

typical practice of our process we use a' f. si() to rubber products or rubber stock made from crude or fresh rubber. y The invention will be' best understood from the following detailed description of referred and specific dproceduresunder our invention; it being un e the particular and specific details are here 'ven, not for the urpose of limiting our invention thereto, making our whole invention, as well as a preferred and specific embodiment of it, clear and intelligible to those skilled in the art.

In this description we shall illustrate our \in any' suitable manner; as b invention as applied to use of old tire stock; but it will be apparent, from the description, that other old rubber stock may be For instance, in a mixture in the proportion` of about 1 to 4 of old inner tubes (relatively soft rubber) and old solid tires, `or otherI tread stock (relativelyl hard rubber.) We ind that this mixture gives the best results for making tire treads and the like; although a reater or lesser proportion of inner' tube ru lber may be used, or the inner tube rubber or the tread stock rubber ma be entirely dispensed with. The general tc aracteristics of the `stock which we begin with depends 'very largely,

if not entirely, upon the character of theY final rubber that we wish to produce. Generally speaking, our process re-vitalizes the rubber in such a manner that our final prod-v uct is substantially the saine as the original substance was when it was new and fresh. That is, for instance, if we treat by'our recess the rubber of an old tire casing, our nal roduct is substantially the same as l that tlre casing was when it was! new. Ac-

cordingly, we make an original mixture to Bpeeication ot Letters Patent.'

Application led December 13, 1920. Serial No. 430,291. I

rstood'however, that ut for the purpose of-V suit the desired qualities of the final product. I n the particular illustrations we are here giving tlielinal product desired is a tread strip fora pneumatic tire; and the proportions of old rubberstock hereinabove stated are good for. that purpose. f-

Patented J une v14, 1921. Y

We next grind up theV selected'stock' and mix it thoroughly. l It is preferred to d the stock as ne as possible and it is esirable to mix as thoroughly as possible. Thisy operation of coinminution and mixingmay. beeasily carried out in machines 'known to the art; or we have found it effective to perform the grinding on abrasive wheels,.such as a carborundum wheel. Foreign material may be removedfin any suitable manner of whichl there are several known in the' artiy Thls finely ground stock, having .been thoroughly mixed/,is then put into ya mold of the desired configuration, `where it` is vsub- 'ectedto heat/for aboutforty-Iive minutes.

he heat may be applied by steam; and for this purpose we use .steam yunder about sixty pounds pressure; so that the temperature of the mold and the rubber therein lis kept at about 275"` to 300 F. t'the same time, mechanical pressure is appliedto the rubber clamping down the cover of the'mo'ld., or instance, in forming@4 tread step for'an' automobile` tireiof'average size, say 100 inches longand perhaps 3% inches wide, fa mechanical pressure is put upon the tread step of a4 thou- 1sand pounds or more', and kept` upon it during the forty-five 'minute/period of'heating.' The pressure presses outfandexcludes air `from the rubber during 'the treatment,`the

mold-being a `practically closed 'onel Such a mold isillustrated in the `drawings -in which the figure is'a section of a suitable shown` atB, the pressure'plateat P, the pressure poducing means at 'M and the rubber at I Next the thusl treated rubber is taken' out 10U to cool or a longer period ofltime than that 105 as we will explain. In carrying out the invention 1t is necessary konlythat the A:rubber be allowed to completely cool in order to mold. In the drawings the inold body is obtainl 'satisfactory results although it 'is .usually desirable that it be allowedy to stand 119 15` ithas a consistency and a ger time vthan it takes' for 4it, todool. {sired characteristics. For instance, we may B the time it is cool it is sufiiciently strongv else zinc oxid to and flexible to allow of its belng vhandledfiralproduct.

.and is ,in condition to be subjected' to the 5 5 next step of the process. Within reasonable .limits of time, the longer itis allowed to stand'in the o en, air, the better final quality Y. isobtained. hat is, We may let the thus treated rubber stand a week or a month-in l the open air, with good results; or we may let it' stand even longer. When the treated rubber'is removed' from the mold, it is rela-A tively soft and Weak, and must be lhandled carefully to .prevent breaking. At that time hysical quality ysomewhat comparable' to t at of' a dough cake;` By standing\in the open air, this treated rubber gradually takes on solidity and strength, and becomes, after some time, ver strong.

ext, the tiretread stock` thus formed, is a ain subjected to heat treatment when it is p ac'ed on the tire. In puttin it on the tire it is subjected for a perio of about sixty minutes .to a heat of approximately sixty pounds steam fpressure, 'being 'thus Heated a ain to about 2,7 5 to '300 F.; and is againsu jected to some physical pressure, such as is a plied in an ordinary vulcanizin mold. fter this second treatment, the

ru ber comes out in practically perfect condition, and practically the same as the originalstock was when new.

AAnother featureof our process that we 35 find to be of convenience and value'is this:

that by utting ordinary rubber cement on the stoc after its yfirst treatment While y the stock is hot-putting-on--three or four coats of such cement, one after the other, 40 as fast as the previous one dries, we can, and

do, dispense with the friction gum ordinarily used in vulcanizing tread stock onto pneumatic tires.A After having repared our tread stock in this manner,w1tii the several coats of cement applied while the stock is hot, then when the stock is actually applied ,to thetire, another coatvof cement may be put on andI thetreadthen vulcanized onto Wi the tire as stated. `We find that the tread l 50,\ is4 thus firmly vunited wi h' the tire, Without liability whatever o tearingloo'se.

. ehav'e found that, by selecting the initial stock, we can produce a reclaimed stock of an -desired' characteristic.` Thus, by using sofi` rubber stock, we can turn out, with our process, a soft resilient rubbersimilar to that used in inner tube or similar to that used for rubber bands. On the other hand, b using a rubberstock that was initially har 1 6 we can' produce a .harder grade of nal produict. Furthermore, we may mix -the Toriginal stock to obtain any rdesired final j consistency and quality, as herein described; @and we mayguse, certain chemicals, Well ghfjlmown in thgfprt, for producing certain del "an allowing it to stand inthe air until cool,

" approximately 300 F. for a produce a harder grade of Having described a preferred form of our invention, 'We claim: 70

Vfl. A process of reclaiming rubber, 'including first finely dividing o d rubber stock, then molding it under heavy pressure and subjecting it to heat'during molding, then" then again subjectin it' to heat.

2. A process of rec aiming rubber including firstV finely dividing old rubber stock,I then moldingit under heavy pressure and subjecting it during molding to a temperature of approximately 300 F., then allowing the product to stand in the air until cool, then again subjectin it to a temperature of approximately 300 3. A process .of reclaiming rubber including first finely dividin old rubber stock, then molding it under lieavy pressure and subjecting it to heat during molding for a perlod of approximately forty-five minutes,V thenallowing it'to stand n the air until cool.,v then again subjecting it (to heat for a period of approximately sixty minutes.

4;. A process of reclaimin rubber, including first finely dividing olyd `rubber stock', then molding it under heavy pressure and subjecting. it during moldin to a temperature of approximately 300 for a period of approximately forty-ve minutes, then allowing the product to stand in the air until cool, then again subjecting it to a temperature of-approximately 300 FY. for a period' of aplproximately sixty minutes.

5. `process ofreclaimin rubber, includl` ing first finely dividin o d rubber stools f then molding it under eavy lpressure and subjecting it during molding to a temperature of approximately 300 F.,then allow.- ing the product to stand in the air'until cool, then again subjecting it to a temperature of period "of approximately sixty minutes.

6. A process of reclaimin rubber, including first finely dividin o d rubber stock, then molding it vunder heavy pressure and subjectingit during molding to a tempera- 11 e ture of approximately 300 F. for a period of approximately forty-five minutes, then all, lewin the product to stand in the air until` cool, t en again subjecting it to heat.

7. A process of reclaimin rubber,includ -ing first firmly dividing o d rubber stock, then molding it under heavy pressure andv subjecting it during moldingto a tempera-- ture of approximately 300 for a'period' l of approximately forty-fiveminutes, then 125 allowing the product tostand in the air until cool, then again subjecting it to a'rtemperature of approximately 300- for about sixty minutes. v j SI'A," process of reclaiming rubber, "fi .Id i i "iat ros.

ing first finely dividing 01d rubber stock then have hereunto subscribed our names this molding it under (liieavy preiure al sub- 18th day of Eoeptember,l 1920. jecting it to heat uring n10 ing, t en allowing it to stand in the air until cool, then 5 again subjecting it to a temperature of ap- V proximately 300 F. for aboutsxty minutes. Witness: y

In witnexsisy,V that we claim the foregoing we fVmezNm Eminem. 

